His sketches lay lost for four centuries until found in the 1950s by the Leonardo scholar, Carlo Pedretti.

Now his 15th-Century plans are set to become a 21st-Century reality in the form of "anthrobots", complex space explorers commissioned by Nasa, the American space agency, and shown on BBC One's Tomorrow's World on Wednesday.

Mark Rosheim founded his own robotics company

Mark Rosheim, an American robotics expert, spent five years using Leonardo's detailed observations to design them and delivered a model to Nasa last year.

He said: "His anatomical drawings are unique and they gave me the information I needed to emulate the complex joints and muscles of the human body."

Nasa is now examining the results as it prepares to begin the $18bn space station from where new planetary missions will be launched.

The agency hopes to send the robots up before astronauts to maintain systems and build new structures for a mission to Mars, but the scheme depends on robots dexterous enough to replicate the work of humans.

Five-year project

Mr Rosheim said: "I read a book by Carlo Pedretti. He talked about the robot and I decided to do a little research on my own."

Though Mr Pedretti found the fragments of robot designs scattered through Leonardo's sketch books, he could not work out how they went together.

But Mr Rosheim, using papers held in Florence and the Queen's Collection at Windsor Castle, created a computer animation that reproduces the way he believes Leonardo designed his robot.

He said: "Florence was an incredible place for me to come to - I started to get inside Leo's head - I was walking where he'd walked, seeing what he'd seen.

"His anatomy drawings were an inspiration, and I began to see how I could design my own robot, using his first principles."

Leonardo's original sketches had to be pieced together

Mr Rosheim started with a sketch of the human skeleton, and then recreated it in stainless steel using articulating joints drawn by Leonardo.

Leonardo's robot, drawn in the form of a knight, can wave its arms and move its head using a flexible neck, while opening and closing its anatomically correct jaw.

A mechanical computer in its chest gives power and control for the arms, while the legs are powered by an external crank mechanism.

While Leonardo's original plans used cables, Mr Rosheim used electric linear motors as the robot's muscles.

The actuators are mounted on the limbs just behind the joints they drive, so that the movement mimics the human body.

New uses possible

The wrist, one of the human body's most complicated joints, presented a big challenge to Mr Rosheim, but Leonardo's principles enabled him to build an advanced model.

He said: "We're after that flexible, universal type motion. [The wrist] is able to go side to side and anything in between. It's genuinely a universal joint"

If developed successfully, anthrobots could one day be used in operating theatres, in deep sea exploration and even in the development of new drugs.

And for a man who designed prototypes for modern-day technology such as helicopters and diving equipment, Leonardo's robot will soon be the latest example of the world catching up with his genius - 500 years on.